Citizen Chin's questions

If I implement a brand new GFS backup rotation, where M-Th I'm running incremental backups, and on Friday I run a Full backup, how will the first incremental backup that runs on Monday know what to backup? My understanding is that the incremental (or diffs) are to run after the full runs...that is, they backup what has changed since the last full backup.

I've been reading up on the GFS rotation, and every chart I look at, and explanation that I read, has it with the incrementals (or diffs) running during the week, with the full running on Friday or Saturday. This seems backwards to me, in terms of grouping tapes for weekly sets. Shouldn't each set of weekly tapes you keep have the full backup leading, with the incrementals following???

I'm in the process of designing my first ever backup scheme. I'm completely new to managing data backup, and there are some concepts that I don't totally understand. Here's what I've got so far, and what equipment I'll be using.

There are only three servers that I will be backing up, total data is approx 200Gb. I will be doing weekly full backups on Saturdays, followed by differential backups Mon thru Fri nights. There will also be an end of month full backup that will be stored off site for DR purposes.

Equipment being used: -8 slot tape backup drive -LTO2 tapes -Backup Exec 12.5 with Exchange and SQL Agents

I will be using two sets of tapes, the first for Week 1, and then another for Week 2, which will be alternated back and forth every other week.

So my question is this, how many tapes should I be using in each set? Do I have to use eight since the backup drive accepts up to eight tapes? Will it be thrown off if I put less in?

Secondly, since the diff backups each weeknight will probably only be about 5Gb or so at most, do I need to put in five LTO2 tapes (which hold up to 400Gb) into the media pool, one tape for each night? Or is one sufficient, since it could theoretically hold many weeks worth of diffs?

What I don't understand is if BE selects a new tape for each day, or if it will just continue to append to the same tape until it's full and then roll over to the next one.

Perhaps the easier question to ask, is, if you had the backup equipment and servers to backup listed above, what would your backup design be?

Many thanks....